Casting Accessories

Rock Candy Chooses Material For Climbing Holds

With more than 7.8 million participants* in the U.S., recreational climbing on artificial indoor walls, in recent years, has surpassed outdoor climbing and become a recognized sport with nationwide and international competitions, publications and even a “lingo” unique to wall climbing enthusiasts. To support enthusiasts’ ever-growing demand for varied climbing experiences, manufacturers are producing walls with larger and more challenging surfaces, routes and holds.

Rock Candy LLC, Akron, Ohio, has emerged as a popular supplier of climbing holds that feature multiple textures, colors and a broad range of shapes and sizes that simulate real rocks and boulders. The rigid polyurethane holds are sold throughout North America and in Japan to commercial and university climbing gyms as well as for residential wall installations.

* 2008 Superstudy of Sports Participation

According to Rock Candy Owner Nathan Yokum, “The Innovative Polymers polyurethane that we use plays a major role in the durability of our holds as well as the challenge that the holds present to climbers.” He continues, “We tested many different materials with a Shore hardness in the 65 to 75D range before selecting the Innovative Polymers product. Innovative Polymers polyurethanes are formulated without chemicals such as mercury, MOCA or TDI and are easy to work with even in producing holds with complex contours and intricate details. The system we use also produces cured holds that combine toughness and rigidity to resist edge breakage and chipping.”

Innovative Polymers also offers a unique color-matching service. This facilitates Rock Candy’s ability to manufacture holds in highly popular colors such as pink, blue and orange as well as a rainbow assortment of other shades. This capability is a key to the company’s success because the colored holds produce aesthetically pleasing walls and, more importantly, are often used to identify climbing routes. The solid-cast, pigmented polyurethane holds maintain consistent, quality color even after supporting hundreds of climbers and being cleaning to remove chalk residue and other contaminants.

Moldmakers begin each new hold design by carving shapes, textures and other details out of polyurethane foam. The resulting patterns are used to build single- or multi-cavity silicone rubber molds. After the molds are fully cured, surfaces are coated with release agent. Then, parts are poured and allowed to cure for about an hour at room temperature, depending on mass size.

Yokum reports, “The Innovative Polymers polyurethane can be cast by technicians without requiring a lot of training because it has an easy to handle, water-like viscosity and a 1:1 resin:hardener mix ratio by volume.” The polyurethane has a 7-to-9 minute gel time that is long enough for casting holds of all sizes and thicknesses even when using multi-cavity molds. Once cured, the polyurethane exhibits a flexural modulus of 200,000 psi and good tensile strength.

About Rock Candy Holds:

Rock Candy Holds has been manufacturing high quality polyurethane climbing holds for more than three years. The distinct line of holds available from the company is designed to add a new and exciting element to climbing gyms. Rock Candy works closely with route setters and climbing gym owners to determine which products will best meet the needs of each facility.

About Innovative Polymers:

Innovative Polymers was formed in 1992 to provide prototypers and parts manufacturers with a full line of advanced polyurethanes as well as custom-formulated products. The company specializes in rapid, cost-effective response to customer needs. Operating from a manufacturing plant that is designed for bulk as well as custom material production, Innovative Polymers also maintains a fully equipped laboratory for research and development and quality control facilities.